742 CATALOGUE OP THE DESCRIBED HYMENOPTERA OF AUSTRALIA 



VENUSTA, Sm. I.e. p. 26, 9. 

 Perth, W.A. 



VIRIDATIS, Sm. I.e. p. 25, (J. 

 Australia. 

 520 viviDA, Sm. New Sp. Hym. Brit. Mus. p. 207, $ (1879). 

 Champion Bay, W.A. 



Family THYNNID^. 



This gi'oup is a very characteristie one among our Australian 

 Hymenoptera, and the genus Thynnus, which is peculiar to 

 America and Australasia, is remarkable for the number and 

 beauty of its species. In the early summer, in a favourable 

 locality, scores of the males of T. variabilis, Kirby, T. leachiellus, 

 Westw., and T. shuckardi, Guer., three of our commonest species, 

 may be seen hovering over the flowers, and seeking the small 

 wingless females. Many of the early entomologists described the 

 sexes as different species, and in this family, and also in the 

 Mutillidoi, it is very difficult to sex any of the species unless they 

 are captured together. As many of the following species have 

 been described from specimens of the one sex, there is, no doubt, 

 a good deal of confusion in this family, and a revision of the 

 Tliynnidoi would be very useful work. Fabricius formed the 

 genus Thynnus in his " Syst. Entoraologica " (1775). M. Guerin 

 in his Memoir of the Thynnidce in the "Voyage de la Coquille" 

 (1830), and afterwards in the "Magasin de Zoologie " (1842), 

 described a large number of new species, and divided them up 

 into a great number of new genera. In 1842, Dr. Klug wrote a 

 monograph of this family in the "Transactions of the Berlin 

 Academy," when he rejected most of Guerin's genera, and, uniting 

 them all under Thynnus, described forty new species. Westwood, 

 in his "Arcana Entomologica" (1845), Vol. II., gives a lot of 

 interesting information about this family, and describes a number 

 of new species which he figures. In the " British Museum 

 Catalogue of Hymenoptera" (1859), Smith catalogued all the 



